1 - Rocks and Minerals and their exploitation

What is the rock cycle?

A representation of the changes between the 3 rock types and the processes causing them

How are igneous rocks formed?

They are made when liquid magma cools to form solid rock

Describe the characteristics of igneous rocks

Extrusive igneous rocks, formed when the rock cools quickly, have small crystals (eg basalt) - intrusive igneous rocks, formed when the rock cools slowly, have large crystals (eg granite)

What are some examples of igneous rocks?

Granite and basalt

How are sedimentary rocks formed?

They are formed by the weathering of existing rocks at the earths surface - sediments (small particles of rocks) accumulate into layers and get pressured due to new deposits above them - these sediments are eroded (transported by water and wind)

Describe the characteristics of sedimentary rocks

Fossils may be present, and particles like clays, silts, sands, gravels and small boulders are also found - there are no crystals

What are some examples of sedimentary rocks?

Limestone, sandstone and shale

How are metamorphic rocks formed?

They are formed from existing rock when heat and or pressure causes changes in the rocks crystals without melting it - these changes can be physical, chemical or both

Describe the characteristics of metamorphic rocks

They don't have fossils but do have mineral crystals present, and are also much harder than sedimentary rocks

What are some examples metamorphic rock?

Marble and slate

What type of extraction does surface mining include?

Open cast mining and strip mining

How does open cast mining work?

It is used when a valuable deposit is located near the surface - the rocks are broken and loosened with explosives, and the loose rock is removed using diggers - the rock or mineral is tipped into trucks or railway wagons - it is mainly used for building materials such as sand, gravel and stone, which are removed from open pits called quarries

How does strip mining work?

Its used to mine a seam of mineral - the overburden (the unwanted overlying rock and soil) is removed as thin strips - it is mainly used to mine coal and lignite

What types of extraction does sub surface mining include?

Deep and shaft mining

How does deep mining work?

A sloping tunnel is used to reach deeper deposits and mining machinery is lowered down, whilst waste rock and mineral ore is hauled to the surface

How does shaft mining work?

A vertical shaft is sunk to the rock layer containing minerals - a horizontal tunnel is made, following the mineral layer - the minerals are extracted by digging by machines and miners, and the loose rock is brought from the mine and piled up on heaps on the surface - these are then transported in trucks or trains

What are the factors that affect the decision to extract rocks and minerals?

Exploration, geology, accessibility, environmental impact assessment and supply and demand

How does geology affect the decision to extract rocks and minerals?

High grade ores yield more of the required chemical elements that low grade ors, so small deposits of high grade ores are worth mining, whilst small deposits of low grade ore that cant be mined at a profit is left as reserves

How does accessibility affect the decision to extract rocks and minerals?

Transporting the ore from mines to processing plants can be difficult and expensive, along with the cost of building roads - carrying out some processing at the mine reduces these costs - the mining company needs a licence to extract a deposit and a long term agreement with the government to avoid tax rises, which makes mining unprofitable

How does an environmental impact assessment affect the decision to extract rocks and minerals?

For the licence to be approved, the company must plan to keep the loss of habitat minimal, and restore the land after finishing mining - the choice of the site for mine waste must be considered

How does supply and demand affect the decision to extract rocks and minerals?

An increase in world demand for any mineral will elevate prices,

The profit from a working mine depends on changes in supply and demand - an increase in world demand for any mineral will elevate prices - if the demand's high, mines that weren't profitable become worth mining, but if the demand falls, working mines may get into a loss due to transport and extraction expenses

What are the environmental impacts of rock and mineral extraction?

There is a loss of habitat so organisms dependant there for food and shelter are affected, noise pollution due to machinery, water pollution making it acidic and unsafe, land pollution as the toxic water doesn't allow plant growth, air pollution bcuz of dust particles and visual pollution

What are the economic impacts of rock and mineral extraction?

Jobs are created for management of waste, extraction and transporting minerals and there is an increase in the country's economy and foreign exchange - the income earned can be used fro buying goods and services and investing in infrastructure projects, such as improving transport

What are the positive social impacts of rock and mineral extraction?

Better standard of life due to economic gain, improvements to services such as healthcare and education and infrastructure projects can help build more well designed communities

What are the negative social impacts of rock and mineral extraction?

Affects the health of labour workers, civilians (due to pollution) and there is a lack of safety

How can mining waste be safely disposed?

Mine waste must be stored to prevent collapse, and the site of mine must prevent the chances of water pollution - the water must be monitored to detect any movement or further pollution

What are the ways to restore land?

Soil improvement, bioremediation and tree planting

How does soil improvement work?

After landfilling, mine waste can be covered by a layer of soil, enriched with fertilisers

How does bioremediation work?

Its the process of removing pollutants from waster using living organisms - microorganisms, like bacteria, can absorb pollutants and metabolise them into less harmful substances

How does tree planting work?

After improving soil fertility, plants and trees can be grown in that area, helping an ecosystem to be reborn

How are nature reserves made from damaged mining land?

Plants are introduced, maintaining biodiversity and creating habitats for many species - these nature reserves become valuable green spaces for human recreation etc

How are lakes reserves made from damaged mining land?

If the rock lining the hole created by extraction is non toxic and impervious to water, it can be filled with water forming a reservoir or lake, which can be used for irrigation farmland or processing to provide clean safe drinking water

How are landfill sites made from damaged mining land?

The waste is tipped into a hole, levelled off and compacting - to make it more sanitary, sometimes some layers of waste are alternated with sand

What is sustainable resource?

A resource that can be continuously replenished - eg agriculture, forestry

What is sustainable development?

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs

What are some strategies for the sustainable use of rocks and minerals?

Increased efficiency of the extraction of rocks and minerals and increased efficiency of the use of rocks and minerals, and the need to recycle rocks and minerals including legislation

How can you increase the efficiency of the extraction of rocks and minerals?

Process mine waste twice so valuable minerals can be recovered, reducing risk of pollution by mine waste - chemical and biological treatment of waste extracts more valuable mineral inside it - also improve performance of machines and more data analysis by computers

How can you increase the efficiency of the use of rocks and minerals?

Engineering solutions - eg design of steel beams with the same strength but using less steel

Why is there a need to recycle rocks and minerals?

Recycling uses less energy than processing ores, and produces less waste, thus reducing the risk of pollution

What is the legislation in terms of the use of rocks and minerals?

The government pass laws that require manufacturers to become responsible for recycling and reuse